1. Technical Field
The present invention is related to molecular cloning of pertussis toxin genes capable of expressing an antigen peptide protective against pertussis. More particularly, the present invention is related to a bacterial plasmid pPTX42 encoding pertussis toxin.
2. State of The Art
Pertussis toxin is one of the various toxic components produced by virulent Bordetella pertussis, the microorganism that causes whooping cough. A wide variety of biological activities such as histamine sensitization, insulin secretion, lymphocytosis promoting and immunopotentiating effects can be attributed to this toxin. In addition to these activities, the toxin provides protection to mice when challenged intracerebrally or by aerosol. Pertussis toxin is, therefore, an important constituent in the vaccine against whooping cough and is included as a component in such vaccines.
However, while this toxin is one of the major protective antigens against whooping cough, it is also associated with a variety of pathophysiological activities and is believed to be the major cause of harmful side effects associated with the present pertussis vaccine. In most recipients these side effects are limited to local reactions, but in rare cases neurological damage and death does occur (Baraff et al., 1979 in Third International Symposium on Pertussis. U.S. HEW publication No. NIH-79-1830). Thus a need to produce a new generation of vaccine against whooping cough is evident.